viruses Flashcards
(15 cards)
What is a virus?
An infectious particle consisting of genes packaged in a protein coat.
Can viruses reproduce or metabolize outside a host cell?
No, they are obligate intracellular parasites.
How do viruses compare to prokaryotic cells?
Viruses are much simpler than prokaryotic cells and are not considered living.
What are the main structural components of a virus?
Genetic material (DNA or RNA) and a protein coat (capsid).
What is a capsomere?
A protein subunit that builds the capsid.
What additional structures might some viruses have?
Membranous envelopes and accessory structures for host cell entry.
What types of nucleic acids can be found in viral genomes?
Either double- or single-stranded DNA or RNA.
What is the structure of a viral genome?
A single linear or circular molecule containing 3 to 2,000 genes.
What are bacteriophages?
Viruses that infect bacteria, with DNA in a capsid head and a tail to inject genetic material.
How do viruses replicate?
By hijacking a host cell’s machinery to produce viral proteins and assemble new viruses.
What does it mean that viruses are “obligate intracellular parasites”?
They require a host cell to replicate and cannot live independently.
What is a virus’s host range?
The specific types of cells or species a virus can infect.
What is an example of a virus with a narrow host range?
Rabies infects only mammals; HIV infects only primates.
What happens once a virus enters a host cell?
It directs the cell to produce viral proteins and nucleic acids, which self-assemble into new viruses.
What host resources do viruses use to replicate?
Enzymes, ribosomes, RNAs, amino acids, ATP, and other cellular machinery.
